Control system for vertical storage equipment

Vertical storage equipment for storing articles comprising:

• a support mechanism movable in opposite vertical directions and supported in the vertical storage equipment, a plurality of carriers connected to said support mechanism at spaced apart locations and motor means and a drive mechanism coupling said motor means to said support mechanism for moving said support mechanism to cause a selected one of said carriers to be moved from a location at which it is stopped and means for stopping said selected carrier at a specified location,
• (a) said drive mechanism including a movable member that moves at a speed greater than the speed of the support mechanism whenever said motor runs and a brake for braking the motor;
• (b) a control system comprising:
• i. a programmed microprocessor controller and manually operated means for input of data to said controller indicative of the carrier that is selected to be moved to said specified location;
• ii. means providing a first reference mark secured to the movable support mechanism and a first sensor fixedly mounted adjacent the path of movement of said support mechanism for sensing the first reference mark when said mark moves past said sensor;
• iii. at least one second reference mark attached to said movable member and a second sensor proximate to said movable member for sensing said at least one second reference mark as said mark moves repeatedly past said second sensor at high speed;
• iv. a flywheel driven rotationally by said motor;
• (c) a motor controller operative to connect said motor to an electric power source and to disconnect said motor from said source in response to start and stop signals generated by said programmed controller,
• (d) said programmed controller responding to input of said data by determining the number of signals that must be produced by said second sensor for said selected carrier to arrive at said specified location, said programmed controller then generating and supplying a start signal to said motor controller and responding to said number of signals having occurred by supplying a stop signal to said motor controller;
• and
• (e) means responding to generation of said stop signal by applying said brake and deenergizing said motor when the selected carrier is still at a predetermined distance from said specified location,
• so that the flywheel inertia aids in continuing movement of said movable support by a predictable amount to accurately and smoothly stop the selected carrier at the specified location.

In combination with vertical storage and retrieval apparatus including frame means, a conveyor supported on said frame means and comprised of flexible loops formed in vertically extending closed loops, rotatable elements on which said loops move such that when at least one of said elements is driven rotationally one side of said loops will move upwardly and the other side will move downwardly, a plurality of article carriers connected to said flexible members in uniformly spaced apart relationship around the loops, an electric motor having a shaft, a speed reducer mechanism having power input means coupled to said shaft and output means coupled to said rotationally driven element to turn it at much lower than motor speed, an electrically operated brake for stopping movement of the conveyor, and an improved control system for positioning a selected one of said carriers at a specific level at a carrier access station, said system comprising:

• programmed processor means having input and output means,
• first sensor means located at a reference position proximate to the path of movement of said conveyor and operative to generate a zero reference signal each time said conveyor passes through said reference position and means coupling said reference signal to said input means of said processor means,
• a member driven rotationally by said motor shaft and marker means defining equiangular rotational increments on said member;
• second sensor means located proximate to said member and responsive to the passing of each marker means by producing electric pulses, and means for coupling said pulses to said input means of said processor means, said processor means being operative to count the number of said pulses between successive reference signals and to divide said number by the number of carriers to determine and store the number of pulses representative of the distance between carriers,
• a motor controller operative to connect said motor to an electric power source and to disconnect said motor in response to motor start and stop signals, respectively, from said processor means,
• means for the user of said storage and retrieval apparatus to input to said processor input means data identifying the carrier desired to be positioned at said specific level at said access station, said processor means responding to said data by providing a start signal to said motor controller to energize said motor to start driving said conveyor and the identified carrier toward said specific level at said access station, said processor means being operative to compare the number of counts the identified carrier is away from said level with the number of counts said carrier was away from said level at the time of said start and signal at a predetermined number of counts before said level is reached said processor means providing a signal to said motor controller to deenergize said motor.